There are numerous unbound manuscripts of LU Xun collected in the National Library of China. Beginning in 2013, research was carried out in order to evaluate the performance of preservation bags used to store the manuscripts. Simulation tests were used to determine the state of degradation of handmade and printing paper previously stored in certain bags.Performance of the preservation bags made from different materials could be evaluated by measurements of the physical properties of the paper. All sulfite process paper bags and other similar varieties are not good for the preservation of the manuscripts. Appropriate acidfree paper preservation bags should be used for this purpose.